====== Netzwerkkonfiguration ======

===== Nützliche Befehle =====

<code>
sysctl -w net.ipv4.ip_default_ttl=128   # TTL temp. setzen 128 = Windows default
ping 192.168.1.1                        # Dauerping
ping -c 4 192.168.1.1                   # 4 Pings
netstat -npl                            # offene Ports auflisten
netstat -tulpn                          # offene Ports auflisten
ss -tulpn                               # offene Ports auflisten
lsof -i | grep -e LISTEN                # offene Ports auflisten
cat < /dev/tcp/127.0.0.1/22             # Teste Ports mit cat

</code>

===== Debian =====
/etc/network/interfaces.d \\
/etc/network/interfaces

<code>
sudo systemctl restart networking.service
</code>

==== Static ====

<code>
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug ens192
iface ens192 inet static
  address 192.168.2.236
  netmask 255.255.255.0
  gateway 192.168.2.254
  dns-domain sweet.home
  dns-nameservers 192.168.2.254 1.1.1.1 8.8.8.8
</code>

<code>
sudo ip addr add 123.222.111.123 dev ens192             #temporär 2. IP hinzufügen (bis reboot)
</code>
==== DHCP =====
<code>
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug ens192
iface ens192 inet dhcp

</code>

===== SLES =====

==== Wichtige Dateien ====

^ Pfad                                          ^ Verantwortlich für            ^
| ''/etc/udev/rules.d/70-persistent-net.rules'' |   |
| ''/etc/sysconfig/network/ifcfg-eth0''         | Beinhaltet die Netzwerkkonfiguration für das Interface "eth0"|
| ''/etc/sysconfig/network/routes''             |   |
| ''/etc/resolve.conf''                         |   |
| ''/etc/HOSTNAME''                             |   |
| ''/etc/hosts''                                |   |


==== Route ====

''/etc/sysconfig/network/routes''

Beispiel
<code>
default 192.168.63.1 - -
</code>

==== Priorität der Adapter ====

''/etc/udev/rules.d/70-persistent-net.rules''

Allgemein
<code>
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="<MAC-Adresse>", ATTR{type}=="1", KERNEL=="eth*", NAME="<ADAPTERNAME>"
</code>
Beispiel
<code>
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:50:56:85:54:00", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"
</code>

==== Netzwerkadapter Einstellungen ====

''/etc/sysconfig/network/ifcfg-eth0''


Beispiel DHCP
<code>
BOOTPROTO='dhcp' 			#or static
BROADCAST=''
ETHTOOL_OPTIONS=''
IPADDR=''				#assigned if static e.g. 10.6.7.203
MTU=''
NAME='AMD PCnet - Fast 79C971'
NETMASK=''
NETWORK=''
REMOTE_IPADDR=''
STARTMODE='auto'
UNIQUE='rBUF.weGuQ9ywYPF'
USERCONTROL='no'
_nm_name='bus-pci-0000:02:01.0'
</code>

Beispiel Statische IP

<code>
BOOTPROTO='static'
BROADCAST=''
ETHTOOL_OPTIONS=''
IPADDR='10.6.7.203'
MTU=''
NAME='AMD PCnet - Fast 79C971'
NETMASK='255.255.255.0'
NETWORK=''
REMOTE_IPADDR=''
STARTMODE='auto'
UNIQUE='rBUF.weGuQ9ywYPF'
USERCONTROL='no'
_nm_name='bus-pci-0000:02:01.0'
</code>

==== Hostname für FQDN ====

''/etc/HOSTNAME''

Allgemein
<code>
<Computername>.<Domain>
</code>
===== DNS-Einstellungen =====

''/etc/resolve.conf''

Allgemein
<code>
domain <Domain>
nameserver <IP_des_Servers>
nameserver <Ggf_IP_des_2._Servers>
</code>

Beispiel
<code>
domain site
nameserver 10.0.0.1
nameserver 10.0.0.2
</code>

===== hosts =====

''/etc/hosts''                                       -> vergleichbar wie in Windows

Allgemein
<code>
127.0.0.1   localhost
<lokale IP> <Computername>.<Domain> <Computername>
</code>

Beispiel
<code>
127.0.0.1       localhost
10.0.0.202      srstef.site srstef
</code>

===== iptables =====

http://jensd.be/343/linux/forward-a-tcp-port-to-another-ip-or-port-using-nat-with-iptables